The present invention relates to a joining device for components in fluid conveyance and distribution systems and, particularly, a joining device for flange connectors for valves and the like. One of the many functions of such joining devices is, for example, to provide a valve or a similar functional assembly with a flanged tubular connector in order to allow the connection thereof with another flanged component.

Flange connectors are known, for example, for valves comprising a tubular portion and a connection flange obtained as one piece with a first end of the tubular portion, in which the connection flange comprises a plurality of holes to accommodate bolts for the connection of a further component of the fluid conveyance and distribution system, for example, a reservoir or a duct with a corresponding connection flange.

A second end (free end) of the tubular portion opposite the first end (flange side) is connected to the valve by means of partial insertion in a tubular length of the latter, and by successive welding or gluing in order to make the connection mechanically resistant and impermeable.

While in this manner a valve is achieved with flanged attachment, the joining device connection by gluing or welding constitutes, on one hand, a mechanically weak point and, on the other hand, it makes an installation fully meeting the measures standardized by the specific technical regulations (for example, ANSI, JIS, DIN) for the individual fluid-technical components difficult. US4007953 and US2002/0135181A1 describe prior art joining devices having the features of the preamble of claim 1.

Therefore, object of the present invention is to devise a joining device for components in fluid conveyance and distribution systems and, particularly, a joining device for flange connectors for valves and the like, which ensures a mechanically resistant connection and, at the same time, preset overall dimensions of the component which it is connected to, as required by the regulations in the subject field.

Within the scope of the main object, a further object of the present invention is to provide a manufacturing method for the joining device, so as to considerably increase the adaptability thereof to different normative standards, and to conciliate a large-scale production with a customization of the product for different markets in which different technical regulations are in force.

These and other objects are achieved by a joining device according to claim 1, and by a method for manufacturing such joining device according to claim 10.

The dependant claims relate to advantageous embodiments.

In order to better understand the invention and appreciate the advantages thereof, some non-limiting, exemplary embodiments thereof are described herein below, with reference to the annexed drawings, in which:

Fig. 1 is a partially cut-away, perspective view of a joining device according to an embodiment of the invention;

Fig. 2 is a front view of the device in Fig. 1;

Fig. 3 is a sectional view along the line III-III in Fig. 2;

Fig. 4 is a perspective view of the device in Fig. 1;

Fig. 5 is an exploded perspective view of the device in Fig. 1;

Fig. 6 is an exploded side view of the device in Fig. 1;

Fig. 7 is a sectional view along the line VII-VII in Fig. 6;

Fig. 8 is a perspective view of a withdrawal-prevention insert of the device according to an embodiment ;

Fig. 9 is a rear view of the insert in Fig. 8;

Fig. 10 is an enlarged view of the detail X in Fig. 9;

Fig. 11 is a sectional view along the line XI-XI in Fig. 9;

Fig. 12 is an enlarged view of the detail XII in Fig. 11;

Fig. 13 is an enlarged view of the detail XIII in Fig. 11;

Fig. 14 is a sectional view of a flanged tubular portion of the joining device according to an embodiment;

Fig. 15 is an enlarged view of the detail XV in Fig. 14;

fag. 16 is an enlarged view of the detail XVI in Fig. 14;

Figs. 17 and 18 are perspective views of a ring nut of the joining device according to an embodiment;

Fig. 19 is a sectional view of the ring nut in Fig. 18.

With reference to the Figures, a joining device for components in fluid conveyance and distribution systems, particularly a flanged joining device for valves and the like is generally indicated with the reference numeral 1.

The device 1 comprises a preferably cylindrical tubular portion 2 with circular annular cross-section; a connection flange 3 obtained as one piece with a first end 4 of the tubular portion 2; one or more seats 5 formed in an outer surface 6 of the tubular portion 2 in the proximity of a second end 7 thereof; at least one withdrawal-prevention insert 8 couplable with the seat 5 so as to form a shoulder which radially projects from such outer surface 6; as well as a threaded ring nut 9 having a countershoulder 10 which is configured so that, when the withdrawal-prevention insert 8 is disconnected from the seat 5, the ring nut can be inserted onto the tubular portion 2 and extracted therefrom and, one the withdrawal-prevention insert 8 has been coupled with the seat 5, the withdrwal-prevention insert 8 engages the ring nut 9 counter-shoulder 10, thus connecting the ring nut in a traction resisting manner to the tubular portion 2.

In this manner, it is possible to connect the device 1 to a valve in order to provide it with a flanged attachment by screwing the ring nut 9. Furthermore, the preset positioning of the seat 5 relative to the connection flange 3, and the seat 5 distance from the second end (free end) 7, ensure a preset standard measure for the valve, including the flanged attachment.

In accordance with an embodiment, the connection flange 3 is configured as an annular plate which is substantially circular and perpendicular to a longitudinal axis L-L of the tubular portion 2, and comprises a plurality of (preferably four) through holes 11 adapted to receive securing bolts (not shown) for the connection of the flange 3, by means of the interposition of an O-ring or other gasket, to a corresponding connection flange of a further fluid-technical device, e.g., a reservoir, a duct, a valve, etc.

The through holes 11 are advantageously arranged with a constant angular pitch around a circle which is concentric to the longitudinal axis L-L. In a rear surface 12 of the flange 3 facing the tubular portion 2 free end 7, bolt seats 13 can be formed embossed around the holes 11 in order to more easily receive the nut or head of the respective bolt without interfering with the room taken up by the ring nut 9.

Between two holes 11, respectively, the connection flange 3 has, in the rear surface 12 thereof, reinforcing ribs 14 joining to the tubular portion 2 so as to increase the mechanical strength of the connection between connection flange 3 and tubular portion 2.

In accordance with an embodiment, in a front surface 15 of the connection flange 3 opposite the rear surface 12 and intended to abut against a corresponding connection flange of another fluid-technical component, annular grooves 15 can be obtained which are adapted to increase the engage with a gasket, for example an O-ring.

The seat 5 can be obtained as a preferably but not necessarily annular circumferential groove essentially extending all around the tubular portion 2 outer surface 6.

Advantageously, the seat 5 has a rectangular shape in cross-section.

With particular advantage, tubular portion 2 along with the connection flange 3, or similar connecting portion, are obtained in large series as one piece by injection moulding and stored, while the seat 5 and, if needed, a cut to measure of the tubular portion 2 second end 7 are subsequently made by means of mechanical processing, so as to customize the device 1 for the several technical regulations in force and for the customers' needs.

The ring nut 9 has a preferably cylindrical, internally threaded side wall 16 with a front edge 17 defining a passage opening 18 and constituting the counter-shoulder 10.

According to an embodiment, the counter-shoulder 10 is configured as a radially inwardly projecting annular wall which extends without interruptions all around the passage opening 18.

Alternatively, the countershoulder 10 can comprise projections which are discontinuous or discrete.

In a rear edge 19 (free edge) of the ring nut side wall 16, anti-unscrewing little teeth 20 can be formed which are intended to engage corresponding recesses or little teeth formed in the component, for example, a valve, which the joining device 1 is intended to be connected to.

According to an embodiment, the withdrawal-prevention insert 8 has a preferably circular, open ring shape as a whole with a radial through slot 21 allowing the insert 8 to elastically expand during the insertion onto the tubular portion 2 free end 7 before snapping into the seat 5.

In order to promote the withdrawal-prevention insert 8 radial expansion during assembling, it has flexural means, preferably a plurality of notches 22 obtained in a radially inner surface of the insert 8. According to an embodiment, the notches 22 are mostly distributed in the insert 8 half opposite the slot 21. Advantageously, three notches 22 are provided, of which a first notch 22' is in the position radially opposite the slot 21, and the other two notches 22 are at an angle of about 70°-85° relative to the first notch 22'. The notches 22, 22' shape is preferably substantially semicircular.

In accordance with an embodiment, the withdrawal-prevention insert 8 further comprises expanding means which are suitable to open the insert 8 when it is axially pushed on the tubular portion 2 free end 7. Preferably, such expanding means comprise a ramp 23 extending from a prompt seat 24, which is obtained on a front side 25 of the insert 8, to the ridge of an inner locking projection 31 which extends (with or without interruptions) along an insert 8 inner circumference.

The inner locking projection 31 is intended to fit within the tubular portion 2 seat 5 in order to axially lock the withdrawal-prevention insert relative to the tubular portion 2.

In accordance with an embodiment, the inner locking projection 31 has a sectional trapezoidal shape with a sloped front side constituting the ramp 23, and a rear side which is perpendicular to the longitudinal axis L-L and is so configured as to abut against a corresponding seat 5 wall in order to implement a shape coupling which prevents the insert 8 axial withdrawal.

According to an embodiment, the notches 22, 22' are obtained in the inner locking projection 31 so as to divide it in a plurality of lengths arranged in a circumferential sequence.

A radially outer surface of the withdrawal-prevention insert 8 forms an outer locking projection 26, preferably a circumferential shoulder (except for the interruption at the slot 21) with a rest surface 27 essentially perpendicular to the longitudinal axis L-L, and facing the front side such as to engage the ring nut 9 countershoulder 10 to connect the latter to the tubular portion 2.

In order to prevent an accidental expansion of the anti-expansion insert 8 in use, it can comprise special anti-expansion means, particularly an abutting surface 28 which is radially outer and adapted to locate, once the device 1 has been mounted, against a corresponding ring nut 9 radially inner surface 29, which prevents it from expanding.

In accordance with a preferred embodiment, the withdrawal-prevention insert 8 is made in a single piece with a base portion 30 in the shape of a longitudinally cut tube, in which an inner surface of the base portion 30 forms the guide seat 24 and the inner locking projection 31 with ramp 23, and an outer surface of the base portion 30 forms the outer locking projection 26.

In this embodiment, the notches 22, 22' can be formed in the inner locking projection 31, thus dividing it into a plurality of discrete lengths, without decreasing the insert base portion 30 thickness.

As already stated before, the manufacturing of the joining device 1 according to the invention preferably takes place through the following steps:

- manufacturing the tubular portion with connection flange in a single piece by injection moulding;

- manufacturing the ring nut by injection moulding;

- manufacturing the withdrawal-prevention insert 8 by injection moulding;

- determining the seat 5 distance from connection flange 3 and tubular portion 2 second end 7, based on the device 1 future application and relative technical regulation;

- obtaining the seat 5 in the tubular portion 2 and, if needed, cutting to measure the tubular portion 2 second end 7, preferably by mechanical processing.

This allows combining the advantages of a large-scale production with the need to customize the product for different applications and technical regulations.

For the assembling of the device 1, the ring nut is inserted on the tubular portion 2 second end 7 (free end) and, subsequently, the withdrawal-prevention insert 8 is arranged with the guide seat 24 on the tubular portion 2 second end 7 and it is axially pushed. In this manner, the tubular portion end 7 slides on the ramp 23 and widens the insert 8, which elastically bends at the notches 22, 22'. When the insert inner locking projection 31 reaches the tubular portion 2 seat 5, the insert elastically shrinks, and the inner locking projection 31 is inserted in such seat 5, so that outer locking projection 26 along with the rest surface 27 constitute a shoulder integral with the tubular portion which prevents the ring nut 9 from slipping off.

Following these simple assembling operations, the device 1 can be easily connected, through the ring nut 9, to a valve or other fluid-technical component which is desired to be provided with a flanged attachment.

In order to make the withdrawal-prevention insert 8 disassembling from the seat 5 easier, two holes 32 can be provided which are drilled on a rear side of the insert (the only side which is exposed once the insert has been applied) in the proximity of the two free ends adjacent the through slot 21. The holes 32 allow the insertion of a tool for the insert 8 enlargement and successive disengagement.

According to an embodiment of the invention, the withdrawal-prevention insert 8 is made of a polyvinylidene fluoride (PVDF) material, while ring nut and tubular portion with flange or different connection are made of one of the following materials to choose from:

- polyvinyl chloride (PVC) ;

- polyvinyl chloride hydrochloride (CPVC) ;

- polypropylene;

- polyvinylidene fluoride (PVDF) .

Due to the fact that the PVDF mechanical strength is higher than the PVC, CPVC, and polypropylene mechanical strength, the withdrawal-prevention insert can be made only of one material (PVDF) for all four materials optionally selected for the other components of the joining device 1.

It shall be apparent that to the joining device according to the present invention, as well as to the manufacturing method to implement such device, one of ordinary skill in the art, with the aim of meeting specific, contingent needs, will be able to make further modifications and variations, all of which fall anyhow within the protections scope of the invention, as defined by the following claims.